"Assuming Apple is too stubborn to start fixing Aqua now, not to mention the possibility that consumers might hate Aqua and refuse to upgrade or buy new Macs - OS X will still secure and probably expand Apple's pro market. Apple has money, credibility, and good will stocked up, even in this extremely unlikely scenario. At worst, they lose some money, the press and stock market predict doom, and Apple begins fixing the user interface as they should've months ago. Sales would then inevitably pick up once Apple made the few necessary improvements thus showing good faith in their customer base."